This invention relates to methods for cleaving single-stranded deoxyribonucleic acid (DNA).
Zaug and Cech, 231 Science 470, 1986, state that certain ribonucleic acid (RNA) molecules, now called ribozymes, are able to catalyze cleavage and rejoining of single-stranded RNA molecules. This activity appears to be specific for ribonucleotides; no reaction is observed with deoxyribonucleotides. A chain of five deoxyribocytosine residues (dC.sub.5), however, is a competitive inhibitor of cleavage of a chain of five cytosine residues (C.sub.5).
Cech, 236 Science 1532, 1987, describes cleavage of mixed oligonucleotides (containing both ribo- and deoxyribo-nucleotides), but only cleavage between a deoxyribonucleotide and a ribonucleotide is observed. No cleavage is observed between two deoxyribonucleotide residues.
Sugimoto et al., 17 Nucleic Acids Research, 355, 368, 1989, describe a reaction where a circular RNA molecule is opened by addition of a dinucleotide, which may include one or more deoxynucleotides. The dinucleotide is added to the RNA molecule, and the circle opened to form a single fragment. No cleavage of DNA is described.